You can use language strings for tab titles, field titles, and field option labels (if a select type). Example as follows.
Tab Title: MY_TAB_TITLE_1
Language String:
Code:
'MY_TAB_TITLE_1' => 'My Tab',
See the below for language usage information.
www.joomlapolis.com/cb-solutions/languages
Be sure to follow the links on the above page in addition to reviewing your CB 2.0 Primer Book for language usage information. Language files can be found at the below location.
components/com_comprofiler/plugin/language/
Additionally you could use a language override plugin found below, but it's a but iffy whether it'll work properly or not due to plugin load order.
www.joomlapolis.com/forum/6-news-and-publicity/227556-cb-language-override-video-tutorial-resources